css.at-rules.supports.at-rule - missing compat data for @supports at-rule()

[3ru]

What type of issue is this?

Missing compatibility data

What information was incorrect, unhelpful, or incomplete?

BCD has data for @supports in css/at-rules/supports.json, including subfeatures for selector(), font-tech(), and font-format().

It does not currently have data for the new at-rule() support condition function used inside @supports, for example:

@supports at-rule(@starting-style) {}

Proposed BCD path: css.at-rules.supports.at-rule

What browsers does this problem apply to, if applicable?

Chromium (Chrome, Edge 79+, Opera, Samsung Internet)

What did you expect to see?

I expected BCD to have a subfeature under css.at-rules.supports for the at-rule() support condition function, similar to the existing selector(), font-tech(), and font-format() subfeatures.

Did you test this? If so, how?

I checked the current BCD source file:
https://github.com/mdn/browser-compat-data/blob/main/css/at-rules/supports.json

WPT:
https://github.com/web-platform-tests/wpt/blob/master/css/css-conditional/js/supports-at-rule.html

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

• Spec: https://drafts.csswg.org/css-conditional-5/#typedef-supports-at-rule-fn
• WPT: https://github.com/web-platform-tests/wpt/blob/master/css/css-conditional/js/supports-at-rule.html
• Edge explainer: https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/AtRuleFeatureDetection/explainer.md

MDN URL

No response

MDN metadata

No response

[caugner]

Thanks for reporting.

@3ru Are you able to confirm whether this is already supported in any browser?

Assuming it is, this data could only be added manually for now, because it looks like there is currently no collector test for CSS @supports.

[3ru]

I can confirm support in Chrome.

WPT.fyi shows /css/css-conditional/js/supports-at-rule.html passing in Chrome stable 148:
https://wpt.fyi/results/css/css-conditional/js/supports-at-rule.html?run_id=6229891086548992
ChromeStatus also lists this feature without a flag: https://chromestatus.com/feature/5110744177836032

I also checked the collector side and yes I agree this likely needs manual data for now